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Re: Information about LTO
On 5/1/07, Sjodin, Jan <Jan.Sjodin@amd.com> wrote:
Can someone give similar information about LTO? How many people
(full/part time) and how long time it will take? How much work is LTO
compared to the tuple representation?
A vast amount more if we're going to work on LTO with the current
GIMPLE representation, because we'll end up rewriting almost all of it
when the tuples representation is merged.
;-)
More seriously: LTO is, by my uneducated guess, about the same amount
of work as the tuples work. I'm assuming single-language LTO here,
because cross-language LTO is far harder (by the time we get there,
we'll be talking about fixing the Fortran front end to play nice with
the call graph, defining some kind of type system, etc.).
Personally, I think the most useful thing you could do at this point,
is helping with the tuples repesentation, or helping with the
preparations for LTO such as removing lang_hooks and perhaps some
intermediate representation oddities like early uses of DECL_RTL (for
e.g. register variables). I think Kenny has shown that an IL
reader/writer is not an awful lot of work, but IMHO it will be corner
cases like the ones I just mention that will take a little while to
resolve. So, better start early, to make work easier later on.
But as I said, that's just my uneducated guess. I haven't done any
LTO work myself yet ;-)
Gr.
Stevem